"The income part isn’t trivial, unless they find some alternative source of funding"

Addressed within the article by the insider:

For what it's worth, I'm not concerned for Mozilla isn't it running out of money. So long as Google or another large search engine exists, it can get cash. There are also a few other financial stability angles it can do which (frankly) would be better.

Google can easily afford to fund Mozilla, and it can't afford to stop. They still need to act like they aren't a monopoly.